Hugo helberger



(No Model.)

H. HELBERGER.

ELECTRIC HEATER.

Patented Dec. 28,1897

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UNITED STATES PATENT OFFICE.

HUGO HELBERGER, OF MUN IOH, GERMANY.

ELECTRIC HEATER.

SPECIFICATION forming part of Letters Patent No. 596,160, dated December 28, 1897.

Application filed April 29, 1896. Serial No. 589,574. (No model.) Patented in Germany June 10,1894,N0. 83,273; in EnglandJuly 13, 1894,1To.13,594; in Switzerland October 1'7,1895,1 I0.11,058; in Belgium October 29, 1895,110. 118,246; in Italy October 31, 1895, No. 40,045, and in Hungary November 9, 1895, No. 4,347.

To ctZZ whom it may concern:

Be it known that I, HUGO HELBERGER,L citi- Zen of Germany, residing at Munich, Bavaria, Germany, have invented certain new and useful Improvements in Electric Heaters, (patented in Germany June 10, 1894, No. 83,273; in England July 13, 1894, No. 13,594; in Switzerland October 17, 1895, No. 11,058; in Belgium October 29, 1895, No. 118,246; in Italy October 31, 1895, No. 40,045, and in Hungary November 9, 1895, No. 4,347,) and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in electric heaters.

The object of my invention is to produce an electric heater which may be readily and cheaply constructed and which will avoid the necessity hitherto existing of employing wire of expensive material, such as platinum.

The invention consists in the employment of Wire insulated by means of beads of glass, porcelain, or other suitable material, the walls of such beads being very thin and in actual contact with the vessel or body to be heated, the wire thus insulated being coiled around the said vessel or body to be heated and covered on the outside with clay or similar nonheat-conducting material.

In the drawings, Figure 1 is a sectional view ofone form of electric heating device embodying myinvention; Fig. 2, an elevation, partly broken away, of the same; Fig. 3, a detail perspective view of one coil of insulated wire; Fig. 4, a section of wire with its insulatingbead, and Fig. 5 a perspective view of a modified form of my invention.

Referring to the drawings, A is a vessel of metal provided with a flanged edge to, extending outward. Around this vessel is coiled a wire B, on which are strung insulating-beads 0, having thin walls 0, the beads being cylindrical and in close contact with the outside of the vessel A, as shown in Fig. 1. The indicoils.

layer D of refractory material in a plastic condition, this refractory material being preferably fire-clay and being forced into intimate contact with the glass beads, so that it fills up the outer depressions between the beads on the various coils and any spaces which may occur between the ends of the respective beads, while at the same time it will not be able to enter or fill the inner depressions existin g between the beads on the various coils, these depressions formin g hollow spaces E between the points of intercontact of the beads and the exterior of the vessel.

Outside the layer of refractory material, when the latter has dried completely, may be placed a casing F to protect the said refractory material. The flanged edge of the vessel serves to protect the upper edge of the refractory material D and may be soldered to the inner face of the casing F.

A lid G is shown, which maybe constructed in any suitable manner.

The ends of the coil are attached to binding-posts H, suitably insulated in the usual way.

The advantages of my construction are that the thin-walled beads allow a better transmission of heat to the vessel at their points of contact with said vessel. Furthermore, radiation may take place across the inner spaces E from the beads and wire to the vessel, thus materially reducing the great difference llSll ally existing between the temperature of the wire and that of the vessel in those constructions where the heat must force itself through a considerable thickness of insulating material to the vessel. At the same time the outer layer of refractory material prevents the ac cess of air to the wire, and as that in the spaces soon has its small amount of oxygen burned out without materially affecting the wires the continual oxidation of the wire is avoided, and hence there is no need of employing wire of non-oxidizable material, such as platinum, and therefore I may employ Ger- 1nan-silver, copper, and even iron wires with good results. Furthermore, owing to the fact, before stated, that the heat is readily conveyed by radiation across the hollow spaces as well as by conduction through those parts of the beads in contact with the vessel the wire does not attain a temperature so much higher than the vessel, and hence need not be of so great specific resistance, thus requiring less current to generate the heat usefully employed.

I am aware that it is old to string beads or buttons on wires for the purpose of insulating the wires from each other or for keeping them at certain fixed distances apart; but in all these constructions the employment of thin-walled beads in actual contact with the vessel for heating purposes is not disclosed.

I am also aware that it is old to wind a resistance-wire around an enameled Vessel to be heated; but such a construction has the serious disadvantage that the heat generated by the wires will in time cause the scaling and cracking of the enamel, which allows the wires opposite the fracture to come into contact with the metal of the vessel, thereby short-eircuiting and causing the destruction of the wires by overheating. Moreover, such a construction is difficult and expensive, requiring great care to keep one coil of wire properly separated from the adjacent coil or coils. By my construction this is avoided since the glass or other similar beads will not be affected by the heat and, being in direct contact with the vessel to be heated, readily transmit the heat to the same by conduction through the points of contact between the beads and the exterior of the vessel and by radiation from the inner surfaces of the beads to said vessel or other body across the inner spaces E, which radiation is more effective than when the heat is compelled to traverse a layer of enamel at all points. At the same time the wire supplied with beads may be quickly applied to the body to be heated without requiring special skill or care.

Furthermore, I am aware that it is old to embed a wire provided with insulating-buttons in a mass of refractory material, but in this construction the heat from the wires must pass not only through the beads but also must traverse the clay or other refractory material to the body to be heated, and as it will under such construction radiate just as well in a direction opposite to the body to be heated as it does toward said body a great waste of heat occurs.

Attention is called to the fact that in the present invention the beads are in actual con tact with the body to be heated, and by the term the body to be heated is meant the vessel or other similar article whose heating is the final function of any heating device and not an intermediate mass of refractory or other material which is heated for the purpose of giving off its heat to such vessel or other article, the use of such intermediate body or mass being entirely avoided by this invention.

Vhile I have described my invention in connection with a vessel, it is obvious that the latter may be replaced by any body to be heated; also, the beads, instead of being cylindrical, may be prismatic, if desired, as shown in Fig. 5.

IVhat I claim isa 1. In an electric heater, the combination with a body to be heated, said body being a conductor of eleetricity,of a wire surrounding the same, a series of beads of refractory material strung upon the wire and in contact with the body to be heated, and a layer of refractory material outside the beads, substantially as set forth.

2. In an electric heater, the combination with a vessel having outward flanged edges, said vessel being a conductor of electricity, of a wire coiled around the outside of said vessel, a series of thin-walled cylindrical beads of refractory material strung upon the wire and in close contact with each other and with the exterior of the vessel, a layer of refractory material surrounding all the beads and filling the exterior depressions between the same, and a casing outside the layer of refractory material and connected to the flanged edge of the vessel, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

HUGO IIELBERGER.

Witnesses:

A. M. CUISUCHUNG, C. MAYER. 

